Typewriting machine



Sept. 15, 1936. H. plTiMAN l 2,054,095

TYPEWRITING MACHINE FiledJan. '7, 1935 Patented Sept. 15, 1936 UNITED STATES PATENT oFFIcE TYPEWRITING MACHINE Henry L. Pitman, Westfield, N. J., assigner 'to Underwood Elliott Fisher Company, New York, N. Y., a corporation of Delaware 'I'his invention relates to a motor-.driven typing-machine carriage, andl particularly to a carriage-return mechanism in which an electric driving motor is normally silent, the motor being energized concurrently with the operation of a key-controlled clutch to connect the carriage to transmission mechanism operative by the motor.

'I'he motor, started from rest at the beginning of each carriage-return operationfmust be enabled to exercise a suiciently strong torque upon the transmission mechanism in order to overcome with reasonable celerity the inertia of the carriage and other parts.

It has been found that a motor capable of l5 starting the carriage o' with the desired degree of celerity has a. tendency, noticeable particularly in an extended run, to continue to speed up the carriage. It is diilicult to impart to the carriage a reasonably fast,.yet smooth and even return 2o movement, irrespective of the extent of such return movement and undefeated by the accelerating characteristic of the motor.

V It is contrived by this invention to provide a governing device responsive to the speed of the carriage movement, and operative, in the preferred embodiment of the invention, to regulate a friction-coupling device which connects the motor and transmission mechanism. There is shown a reciprocating-carriage starting device which enables the motor, started from rest, to

rapidly start the carriage for a short run. Such starting device is self-adjusting as af torque# transmitter, and it therefore transmits the requisite strong carriage-starting torque from the motor as soon as the latter is started, but

diminishes the torque transmission in proportion' to thetendency of the continuing strong motor torque to overspeed the carriage, in long car- -`riage`return runs. With the use of suchcar- 40 nage-starting device, when practicing the desired speed of carriage-return movement, thet momentum of the carriage, when it approaches the usual carriage-arresting stop, will be sub- Y stantially uniform for long, short, and intermediate carriage-return runs. The impact of the carriage against said stop may therefore be minimized to a degree heretofore unattainable. This is because it is obviously easierI to control the impact arising from a. uniform momentum, than an impact which arises' from the heretofore variable momentum, it being understood that there is the usual unvariably timed disconnection of the motor just before the carriage reaches the stop. A feature. of the invention resides in combining the friction coupling and governing .devices in a simple and compact, unitary assembly. 'I'his assembly is preferably at the juncture of the motor-shaft and a transmission shaft, the two shafts being substantially in axial alignment.

v The motor-shaft presents a. friction-clutch facing preferably in. the form of an outer peripheral surface. Said surface may be frictionally engaged by a spring-pressed shoe or' shoes connected to and rotatable with the other shaft. 'I'hese shoes may be arranged so as to be subject l0 to centrifugal action tending to displace the shoes away from said surface. The centrifugal action may be controlled by the counteraction of the shoe-pressing springs in such mannerthat the frictional -coupling between the shoes and 15 said peripheral surface tends to weaken as the speed of the transmission shaft and hence of the carriage tends to increase beyond a predeterminable limit. Such increase in speed is therefore automatically checked by slippage in 2o the frictional coupling resulting from the weakening of the latter. f

Means are provided to nely adjust the pressure of the shoes uponthe co-operative peripheral surface and thereby not only regulate the 25 speed of the carriage-return movement to the desired maximum, but also assure that the friction coupling shall transmit the requisite torque Y to overcome the inertia at the beginning of a carriage-return run. The invention enables the 30 motor to impart to the carriage a smooth, even movement which is in pleasing contrast to the sustained acceleration of movement heretofore obtaining and which sustained acceleration was deleterious to the life oi' the mechanism. y 85 The shoes may be in the form of arms pivoted to a spider or disk fastenedV to the transmission shaft, the free endsof the arms being weighted forI centrifugal action. The free ends of the arms may be faced with friction material shaped to 40 bear upon the peripheral surface presented by the motor-shaft. Said peripheral surface may moreover be spherical so that the coupling serves as a universal joint between the two/shafts which such coupling connects. Forrea establishing Y the necessary intersection of the two shaft-axes according to the practice obtaining in universal joints, the coupled ends of the/shafts are articulated with one another by means of a siinple ball- 5 and-socket contact. L'I'he ball may be formed at l the end of the tranmission shaft and has its center substantially coinciding with the center of sphericity of the clutch-facing. The socket may. be in the form of a central hole in a member fas- 55 -tened to the motor-shaft and upon which said part of the arm upon the aforesaid peripheral ,upon their respective arms.

surface. so that a rotative displacement of said shell will serve to vary the pressure of the several springs The shell may be secured or fastened in any position within its range of adjustment.

Other features and advantages will hereinafter appear.

In the accompanying drawing, J Figure 1 is a view taken from the rear of the typewriter'showingthe transmission mechanism, motor, and the novel coupling device. Y Figure 2 is a cross-sectional view through the shell surrounding the coupling-device and through the motor-shaft showing details of the shoe forming arms. and ,the springs associated therewith.l y

Figure 3 isa skeleton perspective view showing the motor,l part ofthe typewriter-carriagev and carriage-returncontrol, the transmission vmechanismand the novel coupling-device.

Figure 4 is anY enlarged view of, the couplingdevice in perspective, someof theparts being shown broken away and sectionied to bring out` structural details.

Figures 1 and 3 indicatecarriage-return mechanism of the character shown in my PatentNo. 1,580,326, dated April 13, 1926. 'I'he typewriter indicated herein is the well-known Underwood and includes a machine-frame I8, supporting a carriage-frame II, movable in letter-feed and return directions on front and rear rails, the rear rail I2 being shown-in Figurei.

A carriage-return key-lever I3 is operative to raise the forward end of a link I4 to release the same from a fixed holding plate I5. The released link is drawn rearwardly by a spring I5 to rock a shaft I1, and thereby slide a carriage-returning pinion I8 rearwardly, the pinion being articulated with a partly-shown shift arm I9 operatively connected to the .rock-shaft I1. The earriage-returning pinion I8 has clutch-teeth 20, which, when said pinion is shifted rearwardly, engage a clutch-member 2|, keyed to a shaft 22, on which the pinion I8 is 'slidably mounted. 'Ihe rock-shaft I1 is connected to the rear end of the releasable link I4 by an arm I4* fastened to said shaft. Another arm 23, fastened to said rockshaft I1, enables the latter to operate a switcharm 24 closable upon a xed contact 25, the switch-arm '24 and the arm 23 being connected by the usual link 25.

/Closing of the switch-arm 24 upon the contact 25 connects a normally silent electric driving motor 21.to a source of current-supply represented by leads 28. The rearward shift ofthe carriage-returning pinion I8 into engagement with the clutch-member 2,I is thus attended by energization ofthe normally silent electric motor whereupon the pinion I8 is rotated by said clutchmember 2| to drive the typewriter-carriage frame II in 4a. carriage-return direction through the medium of a rack 29 mounted on said carriage on the usual brackets 3,0.

The usual speed-reducing gearing, generally indicated by the reference number 3|, is provided between the carriage-returning pinion and the Each spring is connected to the shellV to the carriage-frame I I.

me'nt of the rack 29 isutilized for line-spacing a 20 driven by a worm 33, keyed to a shaft 34. A motor-shaft 35 has a oating extension 36 connected thereto by a suitable universal joint 31. YThe 5 motor-shaft extension 36 has its free end in endwise abutment with the end of the worm-shaft 34, said worm-shaft end projecting beyond the usual housing 38, within whichthe reduction gearing is retained.

The novel coupling and speed-controlling means, generally indicated by the reference numeral 39, serveto couple the motor-shaft extension 35 to the worm-wheel shaft 34 and be presently described. 4 l

The carriage-return rack 29 is mounted lupon its supporting brackets 30, so that it is capable of the usual limited endwise movement relative Said endwise moveplaten v4I),- mounted on an axle 4I, journaled in a platen-frame 42, supported by the carriageframe Il. The carriage-return rack has the usual teeth 43 enabling it in said endwise movement to operate a train 44 which includes anf 25 upper arm -45 capable of imparting t the usual line-space slide 46 a rearward line-spacing stroke.

'Said slide carriesthe usual line-space pawl 41 which is co-opera'tive 4with a toothed line-space `'wheel 48, .fastened to the platen-axle. The line- 30v spacing train 44 is substantially as set forth in Patent No.' 1,835,776, to W. F. Helmond, dated December 8, 1931, and is supported on a bracket 50, fastened to the carriage-frame II For guidance in its endwise line-spacing movement the 35 carriage-returnvrack 29 is provided with slots 5I fitting over rearwardly-extendingv arms 52 of the supporting brackets 30. Movement of the rack 29 relative to thecaniageframe II is limited by the striking of the ends lof the slot 5I o against the side edges of the bracket-arm 52. A

spring 54 co-operates to restore the rack and linespace parts to the normal positions seen in Figure 3.

Upon operation of the carriage-return key- 45 lever, the initial portion of the resulting rightward movement of the rack 29 is thus'effective to line-spaceA the platen 40, and when the left end ofthe rack-slot 5I encounters the side edge of the bracket-arm 52, the entire carriage starts on 50 its rightward or return movement. Said rightward movement of the carriage is automatically terminated by the usual means to rock the shaft I1 contrariwise toshift the pinion I8 forwardly to withdraw its teeth from the clutch-member 2 I, 55

and alsoto withdraw the'switch-arm 24'from the xed contact 25 to silence the motor 21.- 'I'he contrariwise rocking of the shaft I1'is also effective tol relatch the link I4 over the holding plate I5. Said return-run-terminating means are fully set forth in' my s aid Patent 1,580,326 and in Patent 1,238,908 to F. A. Hart, dated Sep- 'tember 4, 1917. Briefly described, said means include, see Figure 3, a dog 93* splined to a"`shaft 94 .and coupled to the usual right-hand margin-.f 65

stop 95*L for lateral adjustment with the latter. Said dog, when struck by a carriage-tappet 95* just before the carriage is arrested by said stop 95e, rocks said shaft 94, which, in turn, rocks said shaft n through linkage .s1 forsaid discon- 70 nection of the carriage and'motor.

Heretofore the electric motor 21, starting from rest at each carriage-return operation, returned the carriage at varying rates of speed, depending upon the extent of the can-iage-return run 75 lit and the degree of momentum acquired by the carriage. In an extended run the speed was liable to become unduly accelerated a`s the carriage and driving parts gained in momentum, and the carriage would be projected with undue force against the stop which limits the carriage-return.

To overcome this diiliculty, the novel couplingmeans 39, now to be described, are provided. The

motor-shaft extension 36.has fastened thereto a' part 55, in which the extension 36 is inserted to a limited depth as indicated` in Figures 1 and 4. This leaves at the free end of said part a central hole, the bottom of which is formed by an end 56 of the motor-shaft extension 36. Abutting said end 56 is a ball 51 formed on the end of the worm-shaft 3l and tting the central hole of the part 55. Said part 55 has a ange 53, the outer periphery of which is shaped, see Figures 1 and 4, to form a spherical friction-clutch facing 59. The part 55 is so set on the motor-shaft extension 36 that the center of the clutch-facing sphericity coincides with the center of the ball 51. A set screw 58 secures said part 55 to the motor-shaft extension 36.

A-spider or disk 6l has a hub 62, whereby said disk is fastened to the worm-shaft 34 by a setscrew 63. The outer face of the disk 6| is near the end of the part 55 as in Figure 1, and serves to carry arms 65, shaped to closely surround the clutch-facing 59 as seen in Figure 2. Each arm is recessed as at 64, Figures 2 and 4, to receive and retain a shoe 66, made of friction material and shaped to fully bear upon the spherical clutch-facing 59. Each arm 65 is pivoted upon a stud 68 projecting fromthe face of the disk 6I.

, The rstuds 68 project slightly beyond the arms' 65 to supporta shell 10, having avturned rim 1I which clears the arms 55 andl which may overlap the edge of the arm-supporting disk 6l. The shell 10 and the disk 6I thus form anv enclosure within which the'novel coupling is contained. Said shell also forms an abutment for a compression spring' 12 with which each of the shoearms 65 is provided for the purpose of 1causing its shoe 66 to be pressed upon the spherical clutch-facing 59. The rim 'Il of the shell 10 has accordingly punched inwardly therefrom tongues 13 upon which the springs 12 are s et and retained. The other end of each springv 12 is received in 'a recesslli'ormed outer end ,of thearm whichjhas a jog'61. teclear said spring 12 as seen in rieure mandi also affords readily accessibi the pressure of the springs mmc rovghneaathe shaun fastened to the su rung studs by screws 1s threaded into the ends of midst-.uditi and passing through non 1s formed in the shell. so that thentr may be capable, when the screws 15 are loosened, of` rotative displacement, effective to more or less 'compress the springs 12; and thereby adjust their pressure. The shell 16' has a central .opening clearing the hub-portion of the clutch-facing part 55. y

The electric motor 21 is `fastened by screws 16 to a bracket 19 which is fastened to the backV of the typewriter-frame lil by screws 86. The re duction-gearing housing 39 has a', 'ange ill, whereby it is fastened to the back of the typewriter-frame by screwsv92. F/or the purpose of providing for vup-and-down ,adjustment oit the housing 36 to mesh the carriage-returning pinion Il properly with the teeth of the carriage-returning rack ,29, one ofthe screws 62 passes through a vertical slot 23' in the housing-flange 6|. The other screw is surrounded by 'in eccentric bushhousing may be adjusted up and down, the vertical slot permitting this up-and-downradjustment. The screws 62 are tightened when the adjustment has been eiected.

For supporting the rackr29 against upward thrust, a finger 66. Figure 3, abuts the upper edge of the rack 29 and is carried by the housing 38. To compensate for the up-'and-down adjustment of said' housing, said nger 86 is also made adjustable on said housing, and, to thisl end. is formed as seenin Figure 3, so that it may be secured by screwsl B1. One of said-screws passes through an eccentric bushing 86- which may be so positioned that turning of the'bushing will swing the ng'er 86 up or down, the finger swinglng about the other screw 69.'

The parts constituting the electric switch for the motor may be contained within a hooded portion 89 formed integral with the motor-supporting bracket 19 as seen. in Figure 3. An insulating plate 90 is supported by studs 9i secured to the rear wall of the hood" by` screws 92. Said studs present the insulating plate 90 so that the switchmembers 24, 25, mounted thereon, are in the positions seen in Figure 3.

One of the leads 93 coming from the motor is directly connected to one of the leads 28.- The other lead 93 is connected to the switch-arm 26, and the other lead 26 is connected to a conductorplate 95 bearing theswitch-contact 25 and fastened'to the insulating plate ISil by means of the stud 9i and 'an insulating bushing 96. The insulating plate 90 has a slot 8,5 within which the rear end of the switch-link 26 is sldably supported. d

The novel clutch and speed controller is operative as follows. The springs 912 press the shoes 66 against the spherical clutch-facing 59 with suchforce that when the carriage-return keylever I3 is operated, the frictional connection be-V tweenthe shoe 66 and the clutch-facing 59 is effective to transmit the motor-torquato driveVv the rack 29 for the line-spacing movement and also for the start of the carriage-return movement. As the carriage gains in momentum the motor 21 will speed up, and as it so speedsup, the arms 6.5, .weighted at their free ends by reason of their shape as indicated in Figure 2,V

will tend to swing outwardly against the opposition of the, Aarm-springs. 12.` 'I'his tends to weaken the friction coupling between the shoes 66"argi the :clutch-facing 59, and. at a predetermina lespe'ed of carriage movemeniathere will be a certain slippage between said shoes andfacing which isgeil'ecti've to prevent the carriage speed from exceeding a predetermined maximum. It

will be understood that the springs-12 are prov portioned for 'said maximum speed. and jthat. moreover, their pressure may be adjusted by turning the shells 10. 1| one: way or the other.

VThe novel coupling is thus eifectir to 'transmit from the motorv to the worm-shaft a strong torque at the beginning of the return operation, the transmission being determined the beginning Vof the rotation of the parts,- ex'e't their pre'ssure of the shoe-springs 12, which, atthe fullforce upon the shoes 66. As the speed of Athe Y parts increases up lto the point where the carriage is traveling at the Adesired maximum, the force of the spring l2 is partly overcome the centrifugal action of the arms 65, and the desired maximum speed o f the carriage can never be exceeded because any excess ofspeed is counteracted by increased centrifugal action of the arms 65, which, in turn, vis effective to counteract the spring pressurer to weaken the friction coupling, and thereby automatically check such increase. Should the friction coupling tend to become weakened to the extent that the carnage speed tends coupling,v the springs 'I2 exert to fall below its desired maximum the centrifugal action of the arms 65 will be reduced and correspondingly the friction coupling will be strengthened to maintain the carriage speed at said maximum. 'Ihecarriage speed, after the carriage is tially no slippage in the coupling-means while the carriage, starting from rest, is attaining its said maximum speed.

,if am aware of Patent 1,580,326, granted to me, in which is shown a standard Underwood typewriter-frame and a correspondence-size carriage especially equipped for typing smalltelephone bills; the width of the bill, Figures 1 and 4, being only a fraction of the width of the usual correspondence paper-carriage, and the typed line in the patent being perhaps no more than onethird or 'one-fourth of the length of the usual typed line in typewritten correspondence. Hence,

the carriage-of the patent hasnothingbut short l return runs.` Therefore, the carriage-returning motor maybe directly coupled to the carriagereturning train, andthe coupling may tansmit the full'torque ofthe motor to the carriage-returning train at all'runs.

Owing, however, to the fact that the return run of the carriage is short, there is no oppori tunity for such growing increase in momentum of a heavy carriage, as wouldcause damage at the arrest stop. i Y Inthe presentdnvention, it will be perceived that the carriage-returning electric motor may of the carriage by the usual return be normally idle, and the carriage-return train normally disconnected from said motor, and rapid shortreturn movements of the carriage are limited bythe stop. A normally-closed ,clutch connects the motor tothe carriage-train, and key' operated means start the motor into action and connect it to said train.v Said .clutch is effective to transmit the full driving force of saidmotor to start said carriage during short runs. Said train however has` means to prevent excessive momentum of the carriage due to motor accelera-J tion during along run thereof.- In 'this way, dam-v age from arresting.l theA carriage by said stop in a long run is prevented.. lllfliis preventing means includes apowerful friction clutch between the motor and the carriage-driving gear, which is suflicient-ly effective to maintain lthe full torque of the electric motor upon the carriage when starting and driving it for short runs. Ihe clutch is releasable by centrifugal force during long runs,

to prevent momentum of the carriage from being augmented beyond a predetermined maximum. Hencel the blow delivered by .the carriage against said stop, in terminatingA a long stroke, is about equalized 'with the blow delivered at a short re-A turn stroke. fr

This invention presentsl hthe equivalent of a vpositively coupled motor and carriage, whereby the latter is promptly started for short runs, with 4means to prevent excessive momentum of the carriage due to motor acceleration during a long run thereof, whereby damage from arresting'the carriage by the stop at the end of a long run is prevented. A friction clutch transmits the full torque of the electric motor to the carriage for a short run, without lag between .the carriage and the motor, the clutch being releasable vby centrifugal force during long runs to avoid excessive stop-damaging accumulation of momentum bythe carriage. Hence, short return strokes may be 'made more rapidly, and with consequent increase inaoutput ofthe machine, without incuring danger-,of injury to the 4stop from excessive momentum of the carriage on long runs. By reason of the sphericity of the clutch-facing 59, the novel coupling-means 39 -also actsas a universal joint and therefore the motor-shaft extension 36 need not be in exactly straight alignnient with the worm-shaft 3l. The floating motor-shaft extension 36 facilitates adustment of the housing 38 up or down for securing the proper meshing of the pinion I8 with the rack 29. The point of intersection of the axis of the wormshaft 3l and the more or less divergent axis of the shaft coupled thereto is readily established at the center of sphericity of the clutch-facing by setting the ball 51, at the end of the worm-shaft, to the end of said motor-shaft extension 36. It will be understood that the motor-shaft $5 may be itself coupled to the 'worm-shaft 34 through the medium of the novel coupling-means 39, in" which case' the-floating extension 36 is omitted and the intersection of the axes of shafts 34 and.35 isat the. center of sphericity bf the clutch-facing 59. TheV clutch-facing 59 may be shaped otherwise than spherically provided the coupled shafts are in substantially straight alignment. v y

carriage may be disconnected from th motorrgata suitable instant before the carriage strikeathesual arresting portion 98 of the stop 95, so 1 thatthe carriage has a decelerating momentum when impact of the carriage against said stop-portion occurs. An important advantage Vresulting from the use of theA coupling I9 is that, at said instant of carriage disconnection,

the speed of the carriage `may be substantially uniform for all extents of return run. It becomes lfeasible, therefore, that said instant of disconnection may be the same, in relation to the instant of impact, for all lengths of run, and may therefore be finely timed, to the end' that the emcacy of said deceleration of momentum to minimize the impact of the carriage-against said arresting portion-of the stop is materially improved, and obtainsfor all lengths of carriagereturn run. There is not, as heretofore, objectionable variation of the impact according to the length of the carriage-return run.

Variations may be resorted to within the scope of the invention, and portions of `the improvements may be used without others. 1

Having thus described xn'yfinvention, I claim: 1. The combination of a reciprocatory type,-

writer-carriage, a stop for arresting the return" of the carriage,'a train of mechanism intermittently" rotatabl to' return said carriage, a normally silent''motor having a driving shaftdisposed in substantiallyaxial'alignment 'end -to end with said train, saidshaft presenting at its end portion a friction clutch facing, said train havf fing arrangedat its end portion a shoe freely pressable against said facing, means for pressing 75 "i said shoe against said facing and a centrifugal clutch-releasing device arranged in said train and operative to regulate the lpressure of said shoe against said facing with a force inversely proportional to the speed of said train, said facing, shoe, and clutch-releasing device forming a carriagestarting device whereby the carriage is rapidly started upon energization of the motor and the speed of said carriage is, after starting, maintained substantially uniform irrespective of the length of carriage-return run, said facing and shoe forming a spherical joint so that said shoe and facing may also serve as a universal joint between said train and shaft.

2. The combination of a reciprocatory typewriter-carriage, having a return stop, a train of mechanism intermittently rotatable to return said a shoe freely pressable against said facing, means for pressing said shoe against said facing and a centrifugal clutch-releasing device arranged in said train and adapted to vregulate the pressure of --said shoe against said facing with a force inversely proportional to the speed of said train, said facing, shoe, and clutch-releasing device Aforming a carriage-starting device whereby the carriage is rapidly started upon energization of vthe motor and its momentum is then maintained may also serve as a universal joint between said train and shaft, said shaft and train-ends having ball-and-socket articulation effective to readily establish intersection of the shaft and train axes at the center of the spherical facing.

3. A carriage-return mechanism operable by a normally silent motor and including, in combination, the carriage, a return stop, a train rotatable to return the carriage, a motor-driven shaft aligned end to end with said train, said shaft presenting atitsend a part forming a peripheral friction-clutch surface, said train presenting at its end a spider having pivoted thereon an arm weighted for centrifugal action and arranged to frictionally grip said surface, a spring opposing said centrifugal action and operative to press said arm against said surface, and a shell arranged to form with said spider an enclosure surrounding said shaft and train-ends, and within which said part, said arm, and said springare retained,one end of said spring being connected to said arm and the other end of the springto said shell, said shell being adjustably fastened to said spider, and

being grippable'I manually on its periphery for -rotation relative to said spider for adjusting the to maintain the carriage momentum at aconstant point for all lengths of carriage run;

4. A carriage-return mechanism organization of the character described and having a driving motornormally silent and disconnected therefrom, and having a carriage-return stop, including, in combination, the carriage, a train of mechanism intermittently rotatable to return the carriage, a motor-driven shaft in moreor less slightly divergent alignment end to end with said train, means forming a spherical friction facing, and

other means to frictionally grip said facing, both I of the character described and having a driving motor normally silent and disconnected therefrom, and having a carriage-retum stop, includ-- ing, in combination, the carriage, a train of mechanism intermittently rotatable to return the carriage, a motor-driven shaft in more or less slightly divergent alignment end to end with said train, means forming a spherical friction facing, other 'means to frictionally grip said facing, both means being arranged to frictionally couple said train and said shaft and being operative as a carriagestarting device when the motor is energized and being also operative as a universal joint by reason of the spherical form of said facing, the center of sphericity being at the intersection Aof the divergent axes of the train and shaft, and means articulating said train and shaft end to end and arranged for readily establishing said intersection.

6. The combination of a reciprocatory typingmachine-carriage, a normally silent and disconnected carriage-returning electric motor, a carriage-returning stop, and a carriage-starting device co-operative with means which serve for connecting the carriage and motor and concomitantly starting the motor, said carriage-starting device being a self-adjusting torque-transmitter, said carriage having means effective at the end of its return run to automatically disconnect itself from the motor, said starting device being effective to start the carriage at top speed for either a short run or a substantially longer vreturn run; and having means for automatically adjusting itself to transmit less torque during the long run in proportion to acceleration of carriage speed to prevent the speed from exceeding a predetermined maximum during said long run, whereby the impact of the carriage against said stop is made substantially uniform for all lengths of runs.

7. The combination of ya typig-machine-carriage, and a carriage-driving-train of mechanism connectible to a concomitantly started electric motor for a carriage-return run to an adjustable carriage-stop, said carriage-return run being automatically terminable by the carriage which is operative to disconnect the motor from said driving-train at a predetermined distance of the carriage from said stop to thereby minimize the impact, said distance 'depending on the Vcarriage momentum at the time of motor disconnection, said carriage-driving-train including a normally full-powered but self-weakening torque-transmitting device effective to transmit at the start a` full-strength highest-speed carriage-starting torque, and then, in accordance with the ensuing quick attainment of a predetermined carriage consequence, the impact of the stop-arrested carriage and the final position of the carriage at the trolled to serve to make the typing to begin at a uniform point for'all' lengths of carriage-re- 8. In a-typewriting machine,`.the combination of a reciprocatory carriage, a stop for the returning carriage. a normally silent motor, and means for energizing said motor to drive said carriage for a return run against said stop, said means including a carriage-starting device b'etween the motor and the carriage, to start the latter rapidly, said carriage-starting device in'- cluding means automatically responsiveto the speed of thecarriage, after starting thereof, to slip as the carriage speed increases above the .predetermined starting maximum,-but tog'transmit, without slipping, the full torque of the motor at the start of the latter and thereby start the carriage promptly in full step with the motor, .without lagging of the carriage with respect to the motor. v

. 9. In a typewriting machine, the combination of areciprocatory carriage, a carriage-returning motor, means for causing the motor to drive said carriage, and a stop against which said motor drives said carriage, said means including a carriage-starting yieldable grip device between the motor andthe carriage, eiective to start'the carriage to full speed without yielding of said and arranged to automatically respond to the speed of the carriage, so that the grip yields as the carriage momentum increases above a predetermined maximum, whereby the carriage is',- promptly started. and brought at once to maxi` returning electric motor normally idle, andy a carriage-retm'n train mechanism including means interposed therein for normallymaintaining the carriage disconnected from said motor, of means forl eil'ecting rapid short return movements of the carriage limited'by f'said stop, including a vnornrally-closed clutch connecting the motor to the train, and key-operated means for starting the motor into action and connecting it to the carriage train, said clutch eifective to transmit the full driving force of said motor to start said carriage during short runs, said train having means to prevent excessive momentum of the carriage due to motor acceleration. during a long run thereof, whereby damage from arresting the carriage b y said stop in a long run is prevented, said preventing means including a powerful friction clutch between the motor andthe carriage-driving train which is suiliciently effective to maintain the full torque of the electric motor upon the carriage when driving it for short runs, said clutch being releasable by centrifugal force during long runs, to prevent momentum oi.' the carriage from being augmented beyond a predetermined maxiagainst said stop in terminating a long stroke is about equalized with the blow imparted at a short 4returnstroke; thus permitting increased speed of short return strokes, with consequent increase in the output of the machine.

11. In a typewriting machine, the combination with a carriage, of a mechanism Afor returning the carriage through either very long or very short runs, a stopfor arresting the returning carriage,

accenna end of said return run may be accurately congrip or lagging of the carriage behind the motor,

the carriage, the combination with a carriagemum, whereby the blow imparted by the carriage said returningfmechanism including an electrical motor and a drive-gear-train normally disconnected between said motor and said carriage, to

permit the usual advance movements-of the carriage independently of the motor, said motor being-normally idle, and key means for energizing the motor and simultaneously connecting the carriage to the motor through said train and m'aintaining the connection through a maximum run of the carriage; said carriage-returning train including a normally-closed clutch having a fullpower friction element capable of starting the Carriage and bringing it to full return speed withoutlag of the carriage relatively to the motor, for

eii'ecting quick minimum runs, and also including cen al means for releasing said clutch, to prevent the carriage from gaining excessive momentum during the maximum rims. A

l2. In a typewriting machine, the combination ,Vwith va carriage, of a lmechanism for returning the carriage through either very long orvery short runs, a stop for arresting the returning carriage, said returning mechanism including an electrical motor and a drive-gear train normally disconnected between said motor and said carriage, tof permitthe usual'advance movements of the carriage independentlyof the motor, said motorbeing normally idle, and keyl'means for energiz- Y ing the motor and simultaneously connecting the carriage tol the motor through lsaid train and maintaining the connection through a maximum run of the carriage; said carriage-returning train including a normally-closed clutch having a fullpower friction element capable of starting the carriage and bringing it to full return speed-without lag of the carriage relativelyto the motor, for effecting quick minimum runs, and also including centrifugal means for releasing said clutch, to prevent the carriage from gaining excessive momentum during the maximum runs, said clutch having driving and driven members, one of said clutch members being a plurality of springpressed movable arms, and the other member bea drum, said arms being lined with full-power friction shoes to controlsaid drum .without slip- `ping at the start of the motor and carriage, and

said arms having centrifugal means for releasing said friction members from said drum to prevent the momentum of the carriage from being augmented beyond a predetermined maximum.

13. In a typewriting machine, the combination with a carriage, of a mechanism for returning the carniage through either very long vor very short runs, a stop for arresting the returning carriage, said returning mechanism including an electrical motor and a drive-gear train normally disconnected between said motor and said carriage, to permit the usual advance movements of the carriage independently of the motor, said motor being normally idle, key means for energizing the motor and simultaneously connecting the carriage to the motor through said train and maintaining I ing and driven members, one of said clutch members being Va plurality of spring-pressed movable arms, and. the other member being a drum, said 'arms being lined with full-power friction shoes to control said drum without slipping at the start `of the motor and carriage, and said arms having centrifugal means for releasing said friction members from said drum to prevent the momentum of the carriage from being augmented beyond a lpredetermined maximum, a shell upon which said arms are pivoted, and springs anchored upon said shell and bearing against; said arms, said ,shell being adjustable revolubly to regulate the tension of said springs and thereby varying the power of the clutch to accommodate variticulation to each' other and forming a universal 10 joint, for the purpose set forth. v

, HENRY L. PITlVIAN. 

